When it comes to nature versus nurture, brain scientists think both matter. Daniel Horowitz for NPR hide caption

itoggle caption Daniel Horowitz for NPR

A sixth sense? A small patch of neurons on either side of the brain recognizes how many dots are on a screen. As more dots appear, active neurons shift to the right. Courtesy of Ben Harvey/Utretch University hide caption

itoggle caption Courtesy of Ben Harvey/Utretch University

Language may have evolved in concert with tool making. Sergey Lavrentev/iStockphoto.com hide caption

itoggle caption Sergey Lavrentev/iStockphoto.com

Acting as a "sender," brain researcher Rajesh Rao watches a video game and waits for the time to hit the "fire" button. But he'll only think about doing that — the impulse was carried out by someone in another building, in a recent test of brain-to-brain communication. University of Washington hide caption

itoggle caption University of Washington

Could the images common in accounts of near-death experiences be explained by a rush of electrical activity in the brain? Odina/iStockphoto.com hide caption

itoggle caption Odina/iStockphoto.com

Instructional assistant Jessica Reeder touches her nose to get Jacob Day, 3, who has autism, to focus his attention on her during a therapy session in April 2007. Rich Pedroncelli/AP hide caption

itoggle caption Rich Pedroncelli/AP

Although a flying pig doesn't exist in the real world, our brains use what we know about pigs and birds — and superheroes — to create one in our mind's eye when we hear or read those words. iStockphoto.com hide caption

itoggle caption iStockphoto.com

A window into dreams may now be opening. Silver Screen Collection/Getty Images hide caption

itoggle caption Silver Screen Collection/Getty Images

This image shows a human glial cell (green) among normal mouse glial cells (red). The human cell is larger, sends out more fibers and has more connections than do mouse cells. Mice with this type of human cell implanted in their brains perform better on learning and memory tests than do typical mice. Courtesy of Steven Goldman hide caption

itoggle caption Courtesy of Steven Goldman

Movies like The Shining frighten most of us, but some brain-damaged people feel no fear when they watch a scary film. However, an unseen threat — air with a high level of carbon dioxide — produces a surprising result. Warner Bros./Photofest hide caption

itoggle caption Warner Bros./Photofest